Indeed. I have heard that Walter Pincus, for one, was a cocktail party circuit buddy of Wilson/Plame.
I think Novak's source was somebody in the WH, probably a low-level person. He did say that his source was not particularly partisan.
My guess is that Judith Miller spilled the beans on Plame, as "everybody knew it" -- quite common knowledge in her circles, and it spread around the WH that "Wilson's wife" worked for the CIA. They didn't know her name and, frankly, didn't care. They were outraged that she managed to get her partisan husband on this silly trip.
It may be that Wilson was the genesis of all of this. He wasn't Novak's source, but he may have strutted around Washington, telling all of his friends how he became anti-Bush flavor of the month.
Just as he was coming onboard with Kerry's campaign!